View single post by Mark Rosenbaum
 Posted: 04-22-2007 06:25 pm
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Mark Rosenbaum



Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
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 My car has stock cams and cam timing (110 IN / 110 EX).  The vacuum retard is disabled, and the ignition timing is 12° BTDC.  That's where I get what I consider the best combination of smooth idle, high manifold vacuum, and part-throttle engine pickup.

In comparison, with the timing set to 16° BTDC, the vacuum, idle quality, and low-speed driveability are all noticeably worse.  With the locally available regular fuel, performance does not improve, and I get hints of pinging ('pinking').  With mid-grade fuel, high-end performance is slightly improved but IMHO in a street car such as mine the tradeoffs are not worth the extra fuel cost.